Who shall ascend into the hill of the Lord? The second strophe opens with one of David's sudden transitions. Who is worthy to be brought into contact with a God of such might and glory? Who shall ascend into his hill?
God's "hill" is, in reality, the highest heaven, wherein he has his dwelling-place. Its representative on earth was, at this time, the Mount Zion, where it was already determined in the Divine counsels that the temple should be built, and whither David was now about to transfer the ark of the covenant (see the introductory paragraph).
David asks the question as a warning to the Levites, whom he was about to employ in the transport of the ark, that they might purify themselves in heart and soul before venturing to take part in the solemn ceremony.
Or who shall stand in his holy place? Who, i.e; shall stand and minister inside the tabernacle, when the ark has been placed therein, and it has thus become, in a special sense, God's holy place?